close issue 0081: tables promoted to registry + fn doctor cpp-apps BeginTable check

- docs/TQL.md: añadidas secciones joins, views, main_source, 24 viz tokens completos
  (extraidos de tql_helpers.cpp), color_rules, fn.* builtins completos (20 funciones),
  funciones bloqueadas del sandbox, tabla de estado de implementacion actualizada.
  Nota al pie referencia los 129 checks roundtrip (41 emit + 88 apply).

- functions/infra/audit_cpp_apps.go: añadida AuditCppTableMigration() que escanea
  .cpp de cada app imgui buscando ImGui::BeginTable; status CANDIDATE/MIXED/clean
  segun si usa data_table_cpp_viz en uses_functions.

- cmd/fn/doctor.go: fn doctor cpp-apps ahora incluye seccion BeginTable migration
  con tabwriter CANDIDATE/MIXED; --json produce {conformance, table_migration}.
  doctorAll incluye cpp_table_migration en el mapa JSON.

- .claude/rules/fn_doctor.md: tabla de subcomandos y acciones complementarias
  actualizadas con el nuevo check.

- dev/issues/0081 movido a completed/ con status done y notas de deuda documentadas.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

functions/infra/audit_cpp_apps.go

@@ -157,3 +157,120 @@ func cppHasAutoDockspaceFalse(src string) bool {
 	return strings.Contains(src, "auto_dockspace = false") ||
 		strings.Contains(src, "auto_dockspace=false")
 }
+
+// CppTableMigrationAudit holds the BeginTable migration status for a single C++ app.
+type CppTableMigrationAudit struct {
+	AppID              string `json:"app_id"`
+	DirPath            string `json:"dir_path"`
+	BeginTableCount    int    `json:"begin_table_count"`
+	UsesDataTableViz   bool   `json:"uses_data_table_viz"`
+	Status             string `json:"status"` // "clean", "candidate", "mixed"
+	Message            string `json:"message"`
+}
+
+// AuditCppTableMigration scans C++ apps (imgui framework) for inline
+// ImGui::BeginTable calls and checks whether the app already declares
+// data_table_cpp_viz in its uses_functions.
+//
+// Status values:
+//   - "clean"     — no ImGui::BeginTable found (fully migrated or never had tables)
+//   - "mixed"     — has ImGui::BeginTable AND declares data_table_cpp_viz
+//                   (partial migration OK, wave N in progress)
+//   - "candidate" — has ImGui::BeginTable but does NOT declare data_table_cpp_viz
+//                   (migration not started; consider data_table_cpp_viz, issue 0081)
+func AuditCppTableMigration(registryRoot string) ([]CppTableMigrationAudit, error) {
+	dbPath := filepath.Join(registryRoot, "registry.db")
+	dsn := fmt.Sprintf("file:%s?mode=ro&_foreign_keys=on", dbPath)
+	db, err := sql.Open("sqlite3", dsn)
+	if err != nil {
+		return nil, fmt.Errorf("audit_cpp_table_migration: open db: %w", err)
+	}
+	defer db.Close()
+	if err := db.Ping(); err != nil {
+		return nil, fmt.Errorf("audit_cpp_table_migration: ping db: %w", err)
+	}
+
+	rows, err := db.Query(`SELECT id, dir_path, COALESCE(framework,''), COALESCE(uses_functions,'') FROM apps WHERE lang = 'cpp' ORDER BY id`)
+	if err != nil {
+		return nil, fmt.Errorf("audit_cpp_table_migration: query apps: %w", err)
+	}
+	defer rows.Close()
+
+	var results []CppTableMigrationAudit
+	for rows.Next() {
+		var id, dir, framework, usesFunctions string
+		if err := rows.Scan(&id, &dir, &framework, &usesFunctions); err != nil {
+			continue
+		}
+		if framework != "imgui" {
+			continue
+		}
+
+		absDir := dir
+		if !filepath.IsAbs(absDir) {
+			absDir = filepath.Join(registryRoot, dir)
+		}
+		if _, err := os.Stat(absDir); os.IsNotExist(err) {
+			continue // directory_missing already reported by AuditCppApps
+		}
+
+		// Count ImGui::BeginTable occurrences across all .cpp files (excluding tests/).
+		count := 0
+		err := filepath.WalkDir(absDir, func(path string, d os.DirEntry, walkErr error) error {
+			if walkErr != nil {
+				return nil
+			}
+			// Skip test directories.
+			if d.IsDir() && (d.Name() == "tests" || d.Name() == "test") {
+				return filepath.SkipDir
+			}
+			if d.IsDir() {
+				return nil
+			}
+			if !strings.HasSuffix(d.Name(), ".cpp") {
+				return nil
+			}
+			data, err := os.ReadFile(path)
+			if err != nil {
+				return nil
+			}
+			src := string(data)
+			for start := 0; ; {
+				idx := strings.Index(src[start:], "ImGui::BeginTable(")
+				if idx < 0 {
+					break
+				}
+				count++
+				start += idx + len("ImGui::BeginTable(")
+			}
+			return nil
+		})
+		if err != nil {
+			continue
+		}
+
+		usesViz := strings.Contains(usesFunctions, "data_table_cpp_viz")
+
+		audit := CppTableMigrationAudit{
+			AppID:            id,
+			DirPath:          dir,
+			BeginTableCount:  count,
+			UsesDataTableViz: usesViz,
+		}
+
+		switch {
+		case count == 0:
+			audit.Status = "clean"
+			audit.Message = ""
+		case usesViz:
+			audit.Status = "mixed"
+			audit.Message = fmt.Sprintf("%d ImGui::BeginTable inline (partial migration OK — data_table_cpp_viz already declared)", count)
+		default:
+			audit.Status = "candidate"
+			audit.Message = fmt.Sprintf("candidate to migrate: %d ImGui::BeginTable inline detected, consider data_table_cpp_viz (issue 0081)", count)
+		}
+
+		results = append(results, audit)
+	}
+	return results, nil
+}